Cartridge, converter, or disposable: which should I choose?

Cartridges are the simplest to swap; a converter lets you fill from bottled ink for more color choices and lower long-term cost; disposable pens require no maintenance but are thrown away when empty. Several picks here, including the Lamy Safari and Asvine sets, accept both cartridges and converters, while the Pilot Varsity and EYEYE options are pre-filled or disposable.